Screening of red blood cells for extracellular vesicle content as a product quality indicator

BACKGROUND

The controversy around the quality and clinical impact of stored and differentially manufactured red cell concentrates (RCCs) from different donor groups is ongoing. Current studies are limited by the lack of quality measures suitable for routine screening of RCCs. As extracellular vesicles (EVs) are markers of cellular activation or degradation, this study investigated the utility of EV screening to characterize the effects of RBCs production methods and storage.

STUDY DESIGN AND METHODS

RCCs were prepared by whole blood filtration or red blood cell (RBC) filtration methods, centrifuged to prepare a supernatant, and tested for EV content (dynamic light scattering or tunable resistive pulse-sensing techniques), hemolysis, ATP, and RBC deformability on Days 7, 21, and 42 of storage. To simulate nondestructive quality control (QC) testing, 1 RBC unit was tested in parallel with six 10-mL aliquots that were stored in small-volume containers.

RESULTS

EV content showed a linear increase with storage time (p < 0.001) and correlated with supernatant hemoglobin and inversely with ATP or RBC deformability. The method of component manufacturing influenced the characteristics of the EVs during storage. A strong correlation between both EV testing methods' measure of total EV was observed. EV content in the six aliquots were consistent at each time point but statistically higher than in the original RCCs on and after 21 days of storage.

CONCLUSIONS

EV content correlates with measures of hemolysis and other RBC quality indicators and could be implemented as a routine screening tool for nondestructive QC testing of RCCs.

Effect of Liposome Treatment on Hemorheology and Metabolic Profile of Human Red Blood Cells During Hypothermic Storage

BACKGROUND

Ex vivo cold storage of red blood cells (RBCs) for transfusion has long been associated with hypothermic storage lesions. It has been proposed that liposomes can be used to mitigate hemorheological elements of RBC membrane storage lesions. This study aimed to determine the appropriate liposome treatment time and assess the effects of liposome treatment on RBC's hemorheological and metabolic profiles.

MATERIALS AND METHODS

Unilamellar liposomes were synthesized to contain a bilayer of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC):cholesterol (7:3 mol%). Packed human RBCs (n = 4) were divided into untreated control (HEPES-NaCl solution) and liposome-treated samples (2 mM DOPC liposomes) and treated at days 2, 21, and 42 of hypothermic storage. RBC quality assessment included percent hemolysis, deformability, aggregation, hematological indices, microvesiculation, supernatant potassium, adenosine triphosphate (ATP), and 2,3-diphosphoglycerate (2,3-DPG).

RESULTS

Among the parameters affected by liposome treatment time were deformability, aggregation amplitude (Amp), mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, and microparticle mean fluorescence intensity. After 6 weeks of storage, aggregation index (AI) and Amp were significantly increased in liposome-treated RBCs (AI: 45.38 ± 1.92% vs. 41.54 ± 4.10%, p = 0.020; Amp: 16.38 ± 2.17 arbitrary units [au] vs. 12.22 ± 3.29 au, p = 0.019). Despite comparable hemolysis levels at 3 and 6 weeks, DOPC-treated RBCs showed significantly increased potassium levels for the same time points (3 weeks: 31.2 ± 2.7 mmol/L vs. 30.8 ± 2.7 mmol/L, p = 0.007; 6 weeks: 45.0 ± 3.0 mmol/L vs. 43.8 ± 3.4 mmol/L, p = 0.013). ATP and 2,3-DPG levels were comparable throughout storage.

CONCLUSIONS

Liposome treatment seemed to be more beneficial when performed at the beginning of storage up to day 21. DOPC liposome treatment resulted in an improvement in human RBC hemorheology upon storage, with no significant impact on metabolic profile.

Characteristics of Extracellular Vesicles in Red Blood Concentrates Change with Storage Time and Blood Manufacturing Method

Background

Extracellular vesicles (EVs) in blood products are potential effectors of inflammation and coagulation after transfusion. The aim of this study was to assess the impact of different blood manufacturing methods and duration of hypothermic storage on the EV subpopulations in relation to other in vitro quality parameters of red blood cell concentrate (RCC) products.

Methods

RCCs were produced using whole blood filtration (WBF) or red cell filtration (RCF) (n = 12/method), refrigerated for 43 days, and evaluated for EV size profile and concentration, red cell deformability, ATP and 2,3-DPG, hemolysis, and hematological indices.

Results

The total number of EVs increased significantly with storage in both methods, and WBF-RCCs contained the higher numbers of EVs compared to RCF-RCCs. The concentration of small EVs was greater in WBF-RCCs versus RCF-RCCs, with difference between the two methods observed on day 43 of storage (p = 0.001). Throughout storage, significant decreases were identified in ATP, 2,3-DPG, and EI_max, while an increase in hemolysis was observed in both RCC products.

Conclusion

The dynamic shift in the size and concentration of the EV subpopulations is dependent on the blood manufacturing method and length of storage. Better understanding of the potential clinical implications of these heterogeneous populations of EVs are needed.

Proceedings of the Food and Drug Administration's public workshop on new red blood cell product regulatory science 2016

The US Food and Drug Administration (FDA) held a workshop on red blood cell (RBC) product regulatory science on October 6 and 7, 2016, at the Natcher Conference Center on the National Institutes of Health (NIH) Campus in Bethesda, Maryland. The workshop was supported by the National Heart, Lung, and Blood Institute, NIH; the Department of Defense; the Office of the Assistant Secretary for Health, Department of Health and Human Services; and the Center for Biologics Evaluation and Research, FDA. The workshop reviewed the status and scientific basis of the current regulatory framework and the available scientific tools to expand it to evaluate innovative and future RBC transfusion products. A full record of the proceedings is available on the FDA website (http://www.fda.gov/BiologicsBloodVaccines/NewsEvents/WorkshopsMeetingsConferences/ucm507890.htm). The contents of the summary are the authors' opinions and do not represent agency policy.

Exploring donor and product factors and their impact on red cell post-transfusion outcomes

The impact of donor characteristics, red cell age, and red cell processing methods on recipient outcomes is an emerging area of research. Knowledge generated from exploring this transfusion continuum has the potential to change the way donors are selected and how donations are processed and stored with important clinical and operational impact. Recently, donor characteristics including age, gender, donation frequency, genetics, and ethnicity have been shown to affect product quality and possibly recipient outcomes. The structural, biochemical and immunological changes that occur with red cell storage appear to not cause harm to blood recipients after 14 randomized clinical trials. However, both in vitro and clinical data are now beginning to question the safety of blood stored for a shorter duration. Whole blood filtration, a method of blood processing, has been linked to inferior recipient outcomes when compared to red cell filtration. Collectively, this emerging body of literature suggests that pre-transfusion parameters impact product quality and recipient outcomes and that no 2 units of red cells are quite the same. This review will summarize both the pre-clinical and clinical studies evaluating these associations.

Innocuous Intracellular Ice Improves Survival of Frozen Cells

Extensive efforts to avoid intracellular ice formation (IIF) during freezing have been central to current methods used for the preservation and long-term storage of cells and tissues. In this study, we examined the effect of intracellular ice formation on the postthaw survival of V-79W fibroblast and MDCK epithelial cells using convection cryomicroscopy and controlled-rate freezing. V-79W and MDCK cells were cultured as single attached cells or as confluent cell monolayers. Postthaw cell survival was assessed using three different indices: the presence of an intact plasma membrane, the ability to reduce alamarBlue, and the capacity to form colonies in culture. Regulating the isothermal nucleation temperature was used to control the incidence of IIF in the model systems. We report that the presence of intracellular ice in confluent monolayers at high subzero temperatures does not adversely affect postthaw cell survival. Further, we show that in the absence of chemical cryoprotectants, the formation of intracellular ice alone improves the postthaw survival of cultured V-79W fibroblast and MDCK epithelial cells. Improved long-term storage of cells and tissues will result by incorporating innocuous intracellular ice formation into current strategies for cryopreservation.

The promise of organ and tissue preservation to transform medicine

The ability to replace organs and tissues on demand could save or improve millions of lives each year globally and create public health benefits on par with curing cancer. Unmet needs for organ and tissue preservation place enormous logistical limitations on transplantation, regenerative medicine, drug discovery, and a variety of rapidly advancing areas spanning biomedicine. A growing coalition of researchers, clinicians, advocacy organizations, academic institutions, and other stakeholders has assembled to address the unmet need for preservation advances, outlining remaining challenges and identifying areas of underinvestment and untapped opportunities. Meanwhile, recent discoveries provide proofs of principle for breakthroughs in a family of research areas surrounding biopreservation. These developments indicate that a new paradigm, integrating multiple existing preservation approaches and new technologies that have flourished in the past 10 years, could transform preservation research. Capitalizing on these opportunities will require engagement across many research areas and stakeholder groups. A coordinated effort is needed to expedite preservation advances that can transform several areas of medicine and medical science.

Nanoformulated water-soluble paclitaxel to enhance drug efficacy and reduce hemolysis side effect

Surgery, chemotherapy, and radiotherapy are the three top cancer treatment modalities. Paclitaxel (PTX) is one of the most widely used chemotherapy drugs. However, its clinical applications have been significantly limited due to: (i) serious hemolysis effect of currently available commercial paclitaxel formulations and (ii) its water insolubility. An easy way to deliver paclitaxel by a new nanocarrier system using pluronic copolymers of P123/F68 and Sorbitan monopalmitate (Span 40) was reported in our previous research article. The characterization of the formulation and analysis of drug release and cellular uptake were also presented. In this article, we reported discoveries of our follow-up in vivo antitumor and in vitro hemolytic study discoveries. The experimental results showed that the nanoformulated PTX achieved much better tumor suppression performance while reducing hemolysis side effects. This newly formulated drug can significantly improve patient outcomes in cancer chemotherapy.

Red blood cell membrane water permeability increases with length of ex vivo storage

Water transport across the red blood cell (RBC) membrane is an essential cell function that needs to be preserved during ex vivo storage. Progressive biochemical depletion during storage can result in significant conformational and compositional changes to the membrane. Characterizing the changes to RBC water permeability can help in evaluating the quality of stored blood products and aid in the development of improved methods for the cryopreservation of red blood cells. This study aimed to characterize the water permeability (L_p), osmotically inactive fraction (b), and Arrhenius activation energy (E_a) at defined storage time-points throughout storage and to correlate the observed results with other in vitro RBC quality parameters. RBCs were collected from age- and sex-matched blood donors. A stopped flow spectrophotometer was used to determine L_p and b by monitoring changes in hemoglobin autofluorescence when RBCs were exposed to anisotonic solutions. Experimental values of L_p were characterized at three different temperatures (4, 20 and 37 °C) to determine the E_a. Results showed that L_p, b, and E_a of stored RBCs significantly increase by day 21 of storage. Degradation of the RBC membrane with length of storage was seen as an increase in hemolysis and supernatant potassium, and a decrease in deformability, mean corpuscular hemoglobin concentration and supernatant sodium. RBC osmotic characteristics were shown to change with storage and correlate with changes in RBC membrane quality metrics. Monitoring water parameters is a predictor of membrane damage and loss of membrane integrity in ex vivo stored RBCs.

Quality control of apheresis platelets: a multicentre study to evaluate factors that can influence pH measurement

BACKGROUND AND OBJECTIVES

Blood operators routinely monitor the pH of apheresis platelets as a marker of the so-called storage lesion, which can result from manufacturing problems. It is also suspected that some donor characteristics can increase the risk of poor platelet storage. To explore this hypothesis, we analysed a large, multinational data set of quality control (QC) pH test results on apheresis platelets.

MATERIALS AND METHODS

For the period between September 2011 and August 2014, seven blood operators in Canada, the USA, the Netherlands, the United Kingdom, France and Australia provided pH QC test results and donor characteristics on a total of 21,671 apheresis platelets.

RESULTS

Some variations in pH distribution between blood operators were in part explained by differences in collection, processing and testing methods. Younger age and female gender were significantly associated with a pH value below the 10th percentile. Among donors who had two or more pH measurements (n = 3672), there was a strong correlation between pH results (r = 0·726; P < 0·0001).

CONCLUSION

The strong intradonor correlation of pH measurements and the association between donor characteristics and pH results suggest that donor factors play a role in the quality of platelets.

From Development to Implementation: Adjusting the Hematocrit of Deglycerolized Red Cell Concentrates to Meet Regulatory Standards

BACKGROUND

Before transfusion, thawed frozen red cell concentrates (RCCs) must be deglycerolized. In order to ensure that these products meet regulatory standards for hematocrit, an approach to manipulate hematocrit post deglycerolization was developed and implemented.

METHODS

Glycerolized and frozen RCCs were thawed and deglycerolized using the COBE 2991 cell processor, and the final product's hematocrit was adjusted by addition of various volumes of 0.9% saline / 0.2% dextrose. The in vitro quality of RCCs (hematocrit, hemolysis, hemoglobin content, volume, recovery, ATP, supernatant potassium, and others) were compared to Canadian Standards Association (CSA) and other standards for deglycerolized RCCs.

RESULTS

Addition of saline/dextrose re-suspension solution in a range of 65-90 g post deglycerolization led to acceptable hematocrits. In the pilot study, this approach resulted in RCCs meeting all CSA standards for deglycerolized RCCs, with stimulation of RBC metabolism demonstrated by increased ATP concentration. In the validation phase, results were similar, although the CSA hemolysis standard was not met. Pre- and post-implementation data confirmed that manipulated RCCs met CSA hematocrit standards.

CONCLUSION

This process was implemented at Canadian Blood Services to provide deglycerolized RCCs that meet the CSA hematocrit standard. However, pre- and post-implementation data reveal that this deglycerolization process is not sufficient to have RCCs consistently meet hemolysis standards.

Impact of technical and assay variation on reporting of hemolysis in stored red blood cell products

BACKGROUND

Hemolysis of RBCs is an important measure of product quality and is influenced by donor factors, blood component manufacturing and storage. Percent hemolysis is determined using hematocrit (Hct), supernatant Hb (SHb) and total Hb (THb), each of which can be measured using a variety of methods.

METHODS

Sixteen members of an international collaborative were surveyed to understand equipment and procedural variation in hemolysis testing. In a laboratory-based evaluation, we examined how hemolysis was impacted by: measurement of Hct, SHb, THb and number and force of centrifugations for SHb preparation. The number and size of extracellular vesicles (EVs) was also examined.

RESULTS

There was no consensus in equipment or procedures used by international laboratories to measure hemolysis. The centrifugation force used to prepare samples influenced SHb concentration when a single or double (p=0.0001) centrifugation step was used. The number and force of centrifugation related directly to the ability to remove EVs and EV-bound Hb from samples. Hemolysis varied significantly from 0.16% to 0.32% (mean of 0.22%) depending on the combination of methods or centrifugation conditions used to test expired samples.

CONCLUSION

Method and preparative procedures have a critical impact on measurement of hemolysis in RCC.

Quality Assessment of Established and Emerging Blood Components for Transfusion

Blood is donated either as whole blood, with subsequent component processing, or through the use of apheresis devices that extract one or more components and return the rest of the donation to the donor. Blood component therapy supplanted whole blood transfusion in industrialized countries in the middle of the twentieth century and remains the standard of care for the majority of patients receiving a transfusion. Traditionally, blood has been processed into three main blood products: red blood cell concentrates; platelet concentrates; and transfusable plasma. Ensuring that these products are of high quality and that they deliver their intended benefits to patients throughout their shelf-life is a complex task. Further complexity has been added with the development of products stored under nonstandard conditions or subjected to additional manufacturing steps (e.g., cryopreserved platelets, irradiated red cells, and lyophilized plasma). Here we review established and emerging methodologies for assessing blood product quality and address controversies and uncertainties in this thriving and active field of investigation.

O-Aryl-Glycoside Ice Recrystallization Inhibitors as Novel Cryoprotectants: A Structure-Function Study

Low-molecular-weight ice recrystallization inhibitors (IRIs) are ideal cryoprotectants that control the growth of ice and mitigate cell damage during freezing. Herein, we describe a detailed study correlating the ice recrystallization inhibition activity and the cryopreservation ability with the structure of O-aryl-glycosides. Many effective IRIs are efficient cryoadditives for the freezing of red blood cells (RBCs). One effective cryoadditive did not inhibit ice recrystallization but instead inhibited ice nucleation, demonstrating the significance of inhibiting both processes and illustrating the importance of this emerging class of cryoprotectants.